Tetrakis - hydroxybenzyl phosphonium halides and the preparation thereof



i 3,483,260 I -TETRAKIS'- HYDROXYBENZYL 'PHOSPHONIUM HALIDES AND THE PREPARATION THEREOF Calvin J. 'Worrel,"Detroit, Micl1.,*assig1ior to Ethyl, Corporation, New York, N.Y., a ,corporationof Virginia N Drawing. Filed Oct. 27, 1967, Ser. No. 678,511

Int. Cl. C07f 9/54; C08k 1/60; C10m 1/44 US. Cl. 260-6065 12 Claims ABSTRACT OF DISCLOSURE Tetrakis-hydroxybenzyl phosphonium halides are made i by reacting a hydroxybenzyl halide with one of the following: (1) tetrakis-hydroxyalkyl phosphonium halide, (2) tris-hydroxyalkyl'phosphine oxide, or (3) tris-hydroxyalkyl phosphine. The compounds are antioxidants either alone or in combination with a dialkylthiodialka'noa te synergist. i

susceptible to degradation. Also, newer uses of polypropylene, especially in fabrics, exposes the material to conditions never previously encountered such as high surface area'exposure, dry-cleaningand laundering. Antioxidants Which in the past have served quite effectively to stabilize a broad range of organic materials are no longer satisfactory for use in'many modern plastic applications.

- SUMMARY exceptional stability toa broad range of organic matei rials. In particular this invention relates'to tetrakis-hydroxybenzylphosphonium halides and to their use as antioxidants;

object of this inventiofnisto provide iivmniioxidant compounds and several methods.j'oflpreparing them, A; further object is to .providefa meanspoflstabilizfing ,org'anic vmaterial normally susceptible'todegradation infthe presence 9f oxygenrA still furthertobject' is to provide'po1ypropylene compositions that are exceptionally stable: even. at elevated temperatures. V iDESCRIPTION OF THE PREFERRED a 1 EMBODIMENTS; K i

1 The objects of this invention'are accomplished prog 5;

ing the formula:.

viding tetrakis-hydroxybenzyl phosphonium halides hay- OH2]"P'"X "wherein R and R fa're independently "sel'ectedfrointlic fgroup consisting of -hydrogen,"C alkyl' radical s, 'cgj aryl radicals, C' *cy'cl0alkyl radicals, C 12 aralkyl radicals, andX is-a halogen having an atomic number from ..1 7- 53. Examples of these compounds are:

tetrakis 3-tert butyl imethylQZ-hydroxyb en zyl )phosphonium bromide This invention relates tonew antioxidants that impart .Patenl;ed Dec.*9, 1969 tetrakis(4-hydroxybenzyl)phosphonium chloride tetrakis (2-methyl-5-tert-butyl-4-hydroxyb enzyl phosphonium iodide tetrakis( 3,5 -dimethyl-4-hydroxybenzyl phosphonium chloride tetrakis [3 -sec-dodecyl-5 u-methylbenzyl -4-hydroxybenzyl]phosphonium bromide tetrakis(5-phenyl-2-hydroxybenzyl)phosphonium iodide" tetrakis (Z-methyl-S-sec-butyl- V -hydroxybenzyl) phosphonium chloride i tetrakis(3-tert-amyl-5-cyclohexyl-4-hydroxybenzyl) phosphonium chloride tetrakis 3-sec-decyl-5-benzyl-4-hydroxybenzyl phosphonium chloride tetrakis 3-methyl-4-hydroxybenzyl )phosphonium bromide In one preferred embodiment, the tetrakis-hydroxybenzyl phosphonium halides have the hydroxy radical on the benzyl group located in the -4- position. These compounds have the formula:

R1 "l rro-Gcrm-P-x I iz I4 I wherein R R and X are the same as in Formula I.

Some examples of these compounds in addition to'those previously listed are:

tetrakis 3-tert-butyl-4-hydroxybenzyl phosphonium chloride tetrakis (3 -methyl-S-tert-butyl-4-hydroxybenzyl pho sphonium bromide tetrakis 3 -methyl-5 (a,u-dimethylbenzyl -4-hydroxybenzyl]ph0sphonium iodide tetrakis 3 methyl-5 -sec-butyl-4-hydroxybenzyl )phosphonium chloride tetrakis(3-methyl-S-isopropyl-4-hydroxybenzyl)phosphonium chloride tetrakis 3-sec-dodecyl-4-hydroxybenzyl) phosphonium chloride In a more preferred embodiment the'tetrakis-hydroxybenzyl halides have the formula:

OH I 1 r CH? ,7 i (III) wherein R and are same as-tn Formula R ;is selected from'the group consisting of alpha bianched 'and' C5 eycloalkyl radicaljstThese compounds are distinguished from the broad class of tetr'akisrhydroxybenliy1 phosphonium halides by the'facttha't the hydroxyl'radical on the benzyl group is sterically hindered by at leas't one secondaryor'tertiary radic'al 'ortho to the hydroxyl radical. These compounds are exemplified 'byi I i tetrakis 3-methyl5 tert-butyl 4;hydroxybenzy1 pho s phonium chloride 1" o xy a vdm be anphps hc ium bromide 7. tetrakis 3- u-methylbenzyl .-SgnethyHZ hydrQxyIieniyl phosphoniumchloride f j tetrakis(2-methyl-5cyclohexyl 4 hydroxyberiiii])i5hos+ phonium'bromide H '7 I In a highly preferred embodiment-oithehewJ-cdmpounds the hydroxyl radical is located in the para position on the benzyl group and both positions ortho to the hydroxyl radical are substituted. In this embodiment, the new compounds have the formula:

R L HOQCHJPX wherein R and X are the same as in Formula III and R is selected from the group consisting of C alkyl radicals, C cycloalkyl radicals and C aralkyl radicals. Examples of these compounds are:

tetrakis 3-tert-butyl-5- a-methylbenzyl -4-hydroxybenzyl]phosphonium bromide tetrakis(3,5-diisopropyl-4-hydroxybenzyl)phosphonium iodide tetrakis (3 ,5 -di-sec-butyl-4-hydroxybenzyl) phosphonium chloride tetrakis [3 ,5 -di a-methylbenzyl -4-hydroxybenzyl] phosphonium chloride tetrakis(3,S-dicyclohexyl-4-hydroxybenzyl)phosphonium bromide tetrakis(3,5-di-sec-dodecyl-4-hydroxybenzyl)phosphonium bromide tetrakis(3-tert-butyl-5-benzyl-4-hydroxybenzyl)phosphonium iodide tetrakis (3 ,5 -di-tert-octyl-4-hydroxybenzyl) phosphonium chloride tetr-akis(3,5-di-tert-amyl-4-hydroxybenzyl)phosphonium chloride The most preferred new compound is tetrakis(3,5-ditert-butyl-4-hydroxybenzyl) phosphonium chloride.

The new compounds can be made by several methods. The first method is the reaction of a hydroxybenzyl halide with a tetrakis-hydroxyalkyl phosphonium halide. Both types of reactants are known. For example, useful hydroxybenzyl halides are described in I. Am. Chem. Soc., 77, 1783-5 (1955), and in US. Patent 3,257,321 (June 21, 1966). The tetrakis-hydroxyalkyl phosphonium halides are described by E. L. Gefter, Oragno Phosphorus Monomers and Polymers, pp. 102-3, Associated Technical Services, Inc., Glenridge, NJ. (1962), and by G. M. Kosolopotf, Organo Phosphorus Compounds, pp. 81-7, John Wiley and Sons, NY. (1950).

Suitable hydroxybenzyl halides are those having the formula:

OI-I gi -CllzX 1 wherein R, and R are independently selected from the group consisting of hydrogen, C alkyl radicals, C aryl radicals, C cycloalkyl radicals and C aralkyl radicals, and X is a halogen having an atomic number from 17-53; namely, chlorine, bromine or iodine. Examples of these hydroxybenzyl halides are:

3-tert-butyl-4-hydroxybenzyl chloride 3-methyl-5-tert-butyl-2-hydroxybenzyl bromide Z-hydroxybenzyl iodide 3-phenyl-5-rnethyl-2-hydroxybenzyl bromide 3,5-dicyclohexyl-2-hydroxybenzyl chloride 3-methyl-5-(a-methylbenzyl)-2-hydroxybenzyl chloride Z-methyl-5-tert-butyl-4-hydroxybenzyl chloride 4-hydroxybenzyl bromide 2-methyl-5-phenyl-4-hydroxybenzyl iodide 3-cyclohexyl-4-hydroxybenzyl chloride 2-methyl-5-(a-methylbenzyl)-4-hydroxybenzyl bromide 3-sec-dodecyl-4-hydroxybenzyl chloride 3,5dimethyl-4-hydroxybenzyl bromide 2-tert-butyl-5-(a,ot-dimethylbenzyl)-4-hydroxybenzyl iodide 3-(4-tert-butylphenyl)-4-hydroxybenzyl chloride In making the most preferred tetrakis(3,5-di-tert-butyl- 4-hydroxybenzyl)phosphonium chloride the hydroxybenzyl halide reactant is 3,S-di-tert-butyl-4-hydroxybenzyl chloride.

The tetrakis-hydroxyalkyl phosphonium halide reactants have the formula:

wherein R is selected from the group consisting of hydrogen and C alkyl radicals. Examples of these are:

tetrakis-hydroxymethyl phosphonium chloride tetrakis-hydroxymethyl phosphonium bromide tetrakis( l-hydroxyethyl phosphonium chloride tetrakis( l-hydroXypropyl)phosphonium iodide tetrakis( l-hydroxybutyl) phosphonium chloride tetrakis( l-hydroxyheptyl) phosphonium bromide The reaction is carried out by merely mixing the reactants in a suitable vessel. Stoichiometry requires about 4 moles of the hydroxybenzyl halide reactant per mole of the tetrakis-hydroxyalkyl phosphonium halide, but generally an excess is employed. In practice, the use of about 4-6 moles of hydroxybenzyl halide per mole of tetrakishydroxyalkyl phosphonium halide gives satisfactory results.

It is generally preferred to conduct the reaction in a solvent. Useful solvents are those that are substantially inert to the reactants and have some solvent effect. These include hydrocarbons, chlorinated hydrocarbons, ethers, and the like. Suitable hydrocarbons include both aliphatics and aromatics. Examples of aliphatic hydrocarbons are hexane, heptane, isooctane, n-nonane, and the like. Typical aromatic solvents are benzene, toluene, xylene, and the like.

Useful ethers are diethyl ether, tetrahydrofuran, dioxane, ethyleneglycol dimethyl ether, diethyleneglycol dimethyl ether, and the like. Examples of chlorinated hydrocarbons are methylene chloride, chloroform, carbon tetrachloride, 1,1,l-trichloroethane, 1,1,2-trichloroethane, and the like.

Hydrogen halide is evolved during the reaction. For this reason, it is generally preferred to have a hydrogen halide acceptor present. For this purpose tertiary amines are particularly useful. These include pyridine, trimethyl amine, triethyl amine, and the like.

In most cases the reaction proceeds readily at low temperatures. The reaction rate can be raised by operating at higher temperatures. In general, a reaction temperature range of from about 0-200" C. is suitable. A preferred temperature range is from about 20-l00 C.

The reaction is usually complete in about an hour, but varies with the reaction temperature and reactants. In general, reaction periods of from 1-8 hours give satisfactory results.

The following examples serve to illustrate the first method of preparing the new compounds of this invention. All parts are by weight unless otherwise specified.

EXAMPLE 1 In a reaction vessel equipped with stirrer, thermometer, heating and cooling means and provided with a nitrogen atmosphere place 2,000 parts of dioxane, 1,016 parts of 3,S-di-tert-butyl-4-hydroxybenzyl chloride, 142 parts of tetrakis(hydroxymethyl)phosphonium chloride and 400 parts of triethyl amine. Stir for 30 minutes and then warm the mixture to 50 C. Stir at 50-75 C. for 2 hours. Cool to 20 C. and filter off the precipitate. Wash the precipitate once with diethyl ether and then extract the product from the filter cake with hot chloroform. Evaporate the chloroform from the filtrate, leaving the solid product. Recrystallize the product from'm'e'thanj 1, yielding tetr'akis(3,5-diter. b'utyl-4 hydroxybenzyl)phosphohium chloride; 7 7 y In the above example other hydroxybenzyl halides may be substituted to obtain the corresponding product. The following table lists various hydroxybenzyl halides and the .productwhich would 'resiiltff'romit's substitution in the above example.

Product 'Ietrakis(Z-methykEPtert-butyI- 1 4-hydgoxybenzyl)phosphonium Hydi'intybenzyl halide -3,5-dicycl hexyl--hydroxyoenzyl V chloride. a hydroxybenzyl) phosphoruum chloride. 3-tert-bntyl-2 hydroxybeuzyl Tetrakis(3-tert-butyl-2 hydroxychloride. benzyl) phosphomum chlorlde. 3-sec-d0decyl -methy1'2-hydroxy- Tetrakis(3-dodecy1-5-methyl-2- benzyl chloride. hydroxybenzyl)phosphonium -chloride. 3,fi di sec-butyl-4-hydroxybenzyl' Tetrakis(3 5-di-sec-but-yl-4- chloride.

hydroxyb enzyl) phosphonium chloride. I

If desired, the amine hydrogen halide acceptor can be v omitted and the hydrogen halide removed from the product by use of an aqueous wash or vacuum.

A second method of preparing the tetrakis-hydroxybenzyl phosphonium halides is by the reaction of a hydroxybenzyl halide with a tris(hydroxyalkyl)phosphine oxide. The hydroxybenzyl halides are the sameas those previously described for use in the first method of preparing the, compounds of this invention. fIhe tris(hydroxyalkyl)phosphine. oxides are made from the previouslydescribed tetrakis(hydroxyalkyl)phosphonium halides by reaction with lead carbonate (Filipescu et al., Canadian J. of Chem, vol. 41, pp. 821-5, 1963') or with sodium hydroxide, barium hydroxide or calcium carbonate (Hoffman, J. Am. Chem. Soc., 43,. p. 1464, 1921, and Hoffman, J. Am. Chem. $06., 52, p. 2995, 1930). The trisgllydroxyalkyl phosphine oxide used in thesecond method lwher n .Rtjis lte ro the rs res t n f ydrogen and C alkyl radicals. Examples of these reactj ants are:

acceptor, although this is noteritical.

The following examples illustrate thesecond method of preparing the new compounds of this invention.

. benzyl bromide.

6 EXAMPLE 2 In a reaction vessel as described in Example 1 was place 14 parts of tris(hydroxymethyl)phosphine oxide, --l0,0 parts of dioxane and 30.5 parts of triethyl amine. While s*irring,'76.5 parts of 3,5-di-tert-butyl-4-hydroxybenzyl chloride was added at 15-20 C. over a 30 minute period. Stirring was continued for one hour at 20-25 C. and the reaction mixture was then warmed :to 50 C. It was stirred at 50-60 C. for another hour and then cooled to room temperature. The mixture was filtered and the filter cake was washed with ether to remove by-product. It was then extracted with chloroform'to dissolve'the product and the chloroform solution was filtered to remove insoluble material. The filtrate was evaporated, leaving 58.6 parts of a solid product. This product was recrystallized first from an acetone water mixture and then from a methanol water mixture, yielding tetrakis- 3 ,5 -di-tert-butyl-4hydroxybenzyl phosphonium chloride.

EXAMPLE 3 In a reaction vessel place 106 parts of tris(1-hydr0xyethyl) phosphine oxide, 2,500 parts of carbon tetrachloride and 1,600 parts of 3,5-di-(a-methylbenzyl)-4-hydroxybenzyl bromide. Stir the mixture an hour at 2530 C. and then for 2 hours at 90 C. Water wash the resultant mixture and then evaporate oif the s lvent, leaving a solid product. Recrystallize the product from ethanol to obtain tetrakisl3,5-di-(a-methylbenzyl)-4-hydroxybenzyl1phosphonium bromide.

Following the above general procedure, variations may be made in the manner previously described for the first method of making the new compounds. Likewise, other reactants of the same type may be used with good results. For example, the following table lists the pr ducts that are obtained if different hydroxybenzyl halides are substituted.

Tetrakis(3,5-dimethyl-4-hydroxybenzyl) phosphoniurn chloride. Tetrakis(2-methyl-5tert-butyl-4- hydroxybenzyl) phosphonium bromide. Tetrakis(3,5dlcyclohexyl-4- hlglrldrotybenzyl) phosphonium c or e. 3-rnethyl-dphenyl-iZ-hydroxybenzyl Tetrakis(3-methyl-5-phenyl-% chloride. hlyl ldrogybenzyl) phosphonlum c on e. v m

3,fi-dimethyl-ihydroxybenzyl chloride. 2-methyl-5-tert-butyl'4-hydroxy- 3,5-dicyclohexyl-4 hydroxybenzyl chloride.

hydroxybenzyl halide is reacted with atris-hydroxyalkyl phosphine. Suitable hydroxybenzyl halides include all L those .shown as suitable in the first method described for making the new compounds. Suitable phosphines are those. havingthe formula:

(VIII) hydroxyalkyl wherein R is selected from the group consisting; of;hydrogcn andv C alkyl radicals. These compounds are known and may beJprepared by methods such as those .disclosed by Grinshtein 'et, al-.,-Doklady Akad.;.Nauk.

' SS SR, vol.-'l38, pp. 1359-1362 (1961)..Some examples: of 'these materials are: I "tris(hydroxymethyl)phosphine tri(-1-hydroxyethyl)phosphine tris l-hydroxybutyl) phosphine 75 tris( l-hydroxyheptyl)phospliine The process is conducted by merely reacting from about 4-6 mole parts of the hydroxybenzyl halide with one mole part of the tris(hydroxyalkyl)phosphine at a temperature of from about 200 C. The variable conditions such as temperature, solvents, reaction times, and the like, under which the process is carried out are the same as those described in the first method of making the new compounds.

The following examples serve to illustrate the third method of preparing the compounds of this invention.

EXAMPLE 4 In a reaction vessel as described in Example 1 place 62 parts of tris(hydroxymethyl)phosphine, 1,330 parts of 3,S-di-tert-butyl-4-hydroxybenzyl chloride, 2,500 parts of toluene and 320 parts of pyridine. Stir the mixture one hour at 2530 C. and then heat to reflux. Reflux for one hour, cool to room temperature and then wash 3 times with water. Distill off about one-half of the toluene and then cool the reaction mixture, causing the product, tetrakis(3,5 di tert butyl 4 hydroxybenzyl)phosphonium chloride, to precipitate. Other hydroxybenzyl halides can be used in the above example with good results. The following table lists hydroxybenzyl halidesthat can be used in the above example and the resultant product.

Hydroxybeuzyl halide Product 2-methyl-5-tert-butyl-4-hydroxybenzyl bromide.

bcnzyl chloride.

3-cyclohexyl-5-metliyl-4-hydroxybenzyl chloride.

3-1nethyl-5-te1't-butyl-4-l1ydroxybenzyl bromide.

EXAMPLE 5 To a reaction vessel as described in Example 1 add 3,000 parts of diethyleneglycol dimethyl ether, 1,850 parts of 3,5-dicyclohexyl-4-hydroxybenzyl chloride and 352 parts of tris(l-hydroxyheptyl)phosphine. Stir the mixture one hour at 30 C. and then heat to reflux. Stir at reflux for an additional hour and then cool. Add 1,500 parts of water and filter off the precipitate. Recrystallize the precipitate from isopropanol to obtain tetrakis (3,5- dicyclohexyl-4-hydroxybenzyl)phosphonium chloride.

In the foregoing three processes, one reactant, the hydroxybenzyl halide, has been the same while the other reactant can be a tetrakis(1-hydroxyalkyl)phosphonium halide, a tris(l-hydroxyalkyl)phosphine, or a tris(1-hydroxyalkyl)phosphine oxide. It is apparent that mixtures of these phosphorus compounds can be reacted with the hydroxybenzyl halide in place of the individual compounds.

The compounds of this invention are extremely useful as antioxidants in a wide variety of organic material normally susceptible to deterioration in the presence of oxygen. Thus, liquid hydrocarbon fuels such as gasoline, kerosene and fuel oil are found to possess increased storage stability when blended with a stabilizing quantity of an additive of this invention. Likewise, hydrocarbon fuels containing organometallic additives such as tetraethyllead, tetramethyllead, methyl cyclopentadienyl manganese tricarbonyl, cyclopentadienyl nickel nitrosyl, ferrocene and iron carbonyl have appreciably increased stability when treated with the additives of this invention. Furthermore, lubricating oils and functional fluids, both those derived from naturally occurring hydrocarbons and those synthetically prepared, have greatly enhanced stability by the practice of this invention. The additives of this invention are extremely useful in stabilizing antiknock fluids against oxidative degradation. For example, the stabilizing additives of this invention find utility in stabilizing a tetraethyllead antiknock fluid which contains ethylenedichloride and ethylenedibromide.

The additives of this invention are effective in stabilizing rubber against degradation caused by oxygen or ozone. As used in the description and claims, the term rubber s employed in a generic sense to define a high molecular weight plastic material which possesses high extensibility under load-coupled with the property of forcibly retracting to approximately its original size and shape after the load is removed. Some examples are acrylic rubber, styrene-butadiene rubber (SBR), poly-chloroprene, chlorosulfonated polyethylene, fluorocarbon rubbers, isobutyleneisoprene (IIR), isoprene, poly-butadiene, nitrile-butadiene rubber, polyisobutylene rubber, polysulfide rubbers, silicone rubbers, urethanes, India rubber, reclaimed rubber, balata rubber, gutta percha rubber, and the like.

The compounds of this invention are also useful in protecting petroleum wax against degradation. The additives also find use in the stabilization of fats and oils of animal and vegetable origin which tend to become rancid during long periods of storage because of oxidative deterioration. Typical representatives of these edible fats and oils are linseed oil, cod liver oil, castor oil, soy bean oil, rapeseed oil, coconut oil, olive oil, palm oil, corn oil, sesame oil, peanut oil, babassu oil, butter, lard, beef tallow, and the like.

The compounds of this invention are superior antioxidants for high molecular weight homopolymers and copolymers of olefinically unsaturated monomers such as polyethylene and polypropyelne (both high pressure and so-called Ziegler type), polybutene, polybutadiene (both cis and trans), ethylene-propylene rubber, acrylonitrile-butadiene-styrene terpolymer, ethylene-propylenediene terpolymers such as ethylene-propylene-l,5-cyclooctadiene and ethylene-propylene-dicyclopentadiene, and the like.

The amount of stabilizer used in the organic compositions of this invention is not critical as long as a stabilizing quantity is present, and can vary from as little as 0.001 weight percent to about 5 weight percent. Generally, excellent results are obtained when from 0.1 to about 3 weight percent of the stabilizer is included in the organic compositions.

The following examples serve to illustrate the use of the stabilizers of the present invention in stabilizing some representative organic materials normally subject to deterioration in the presence of oxygen or ozone.

EXAMPLE 6 A rubber stock is prepared containing the following components:

Component: Parts Pale crepe rubber 100.00 Zinc oxide filler 50.00 Titanium dioxide 25.00 Stearic acid 2.00 Ultramarine blue 0.12 Sulfur 3.00 Mercaptobenzothiazole 1.00

To the above base formula is added one part by weight of tetrakis (3-tert-butyl-S-methyl-Z-hydroxybenzyl)phosphonium bromide and, following this, individual samples are cured for 20, 30, 45 and 60 minutes, respectively, at 274 C. After cure, all of these samples remain white in color and possess excellent tensile strength. Furthermore, they are resistant to degradation caused by oxygen or ozone on aging.

EXAMPLE 7 A synthetic rubber master batch comprising parts of SBR rubber having an average molecular weight of 60,000, 50-parts of mixed zinc propionate-stearate, 50

parts of carbon black, 5 parts of road tar, 2 parts of sulfur and 1.5 parts of mercaptobenzothiazole is prepared.

681-percent- 1,3-butadiene and 32 percent-acrylonitrile.

-Two percent, based on the weight of the'copolymer; of tetrakis[3 sec dodecyl (u methylbenzyl) 4' hyadroxybenzynphosphonium bromide is added as an aqueousemulsion to the latex obtained from emulsion .copolymerization of the =butadiene and-.acrylonitrile monomers. The latex'is coagulated with aluminum sulfate .-andthe' coagulum, after washing, is dried for 20 hours at 70 C. Thesynthetic copolymer so obtained is. resistant to -oxidative degradation.

" EXAMPLE? @Three percent of, tetrakis(2 methyI S-sec-butyl-4 hy- :droxybenzyl)phosphonium chloride as an emulsion-in sodium oleateis added to, a rubber-like copolymer of 1,3-butadiene and styrenecontaining 25 percent styrene.

.The resulting synthetic elastomer possesses enhanced stability. t

EXAMPLE To a master batch of GR-N syntheticrubber containing 100 parts of GR-N rubber, -5 parts of zinc stearate, I

50 parts of carbon-black, 5' parts of road tar, 2 parts of sulfurandZ parts 'ofmercaptobenzothiazole is added'S percent, based'onweight, of tetrakis(3-sec-decyl-5-benzyl- 4-hydroxybenzyl)phosphonium chloride. After curing, a

synthetic rubber is obtained of improved oxidative stability. 7

"EXAMPLE 11 if: To a master batch of polyethylene having an average molecular weight of 1,000,000, a tensile strength of 6,700

'p'.s.i., a Shore D hardness of 74, and a softening temperature under low load of 150 C., is'added 5 percent of tetrakis(-3,5 di ---tert butyl 4.- hydroxybenzyDphosphoniun chloride. The, resulting polyethylene possesses .st abilityfagainst oxidative degradation and shows no 1 tendency to yellow after extensive aging.

' EXAMPLE 12 A linear polyethylene having a high degree of crystallinity (93 percent) and less than one branched chain per 100 carbons atoms, a density of about 0.96 gram per ml.

and which has about 1.5 double bonds per 100 carbon atoms is :mixed with 0.005 --weight percent. of tetrakis 13-tert-butyl-thydroxybenzyl) phosphonium chloride. The resultingpolyethylene is found to possess stability against oXidatiVeQdegradatiQn. v 1 I zJ AMPLE "To 100 partsof anethylene propylene terpolymer with 1,5-cyclooctadiene isadded 3 parts of tetralris( 3.-me'thy l- '5 tert-butyl-4-hydroxybenzyl)phosphonium bromide, re-

sulting in an ethylene-propylene terpolymerof enhanced stability.

' 5 XAMPLE 14 p To 100 parts of an ethylene-propylene rubber is added 2 parts of tetralgis[3-methyl 5(a, -diinethylbenzyl) 4-hy droXyb'enzyHphosphoniuni iodide, resulting in an'EPR rubber stock of improved stability. I EXAMPLE 15 I "After the ipolymrizationof polypropylene in a hexane 'solv'ent employing a Ziegler catalyst; the catalyst is neutralized with water and tetrakis(3=sec-dodecyl-4-hydroxybenzyl)phosphonium chloride is'added to the mixture in quantities such that, after' evapor'ation'of the solvent, a Ziegler polypropylene is obtained containing'2 percent of tetrakis'(3-- secdodecyl 4 hydroxybenzyl) phosphopolypropylene.

mum chloride. This polypropylene is found to possess excellent stability against degradation caused by oxygen 'or ozone. Furthermore, this polypropylene is found to resist degradation at elevated temperatures, even in the presence of oxygen. During this high temperature aging the Ziegler polypropylene shows no tendency to discolor.

EXAMPLE l6 7 To 1,000 parts of a crystalline polypropylene prepared using a'Ziegler type catalyst is added 1 weight percent of tetrakis(3 methyl 5 tert -'buty1 4 hydroxybenzyl) phosphonium chloride. The resulting mixture is melted and stirred, resulting in a molten polypropylene composition possessing excellent resistance to thermal degradation.

EXAMPLE 17 To 1,000 parts of poly-cis-butadiene dissolved in benzene is added 0.15 weight percent of tetrakis(3-cyclohexyl- 2-hydroxy-benzyl)phosphonium bromide. The resultant poly-cis-butadiene solution is transferred slowly into boil- 'ing water, which causes the water and benzene to codistill, leaving a stabilized poly-cis-butadiene.

" EXAMPLE 1% To 1,000 parts of a crystalline polypropylene made using a Ziegler catalyst is added 1 weight percent of tetrakis[3 tert butyl 5 (a methylbenzyl) 4 hydroxybenzynphosphonium bromide. The mixture is melted and immediately stirred, giving a highly stable EXAMPLE 19 To 1,000 parts of solvent-refined midcontinent neutral lubricating oil containing 0.05 percent Zinc-dilaurylthiophosphate, 4 percent of a poly-laurylmethacrylate VI Improver and 0.05 percent of an overbased calcium sul- "fonate and 2 percent of a dispersant formed by reacting an alkenyl succinic anhydride wherein the alkenyl chain 'is a polybutene with a molecular Weight of about 1,000

with tetraethylene pentamine is added 0105 percent of tetrakis(3,5 di sec butyl 4' hydroxybenzyl)phosphonium chloride. The resultingoil is resistant to therrna and oxidant deterioration.

EXAMPLE 20 To 1,000 parts of an acrylonitrile-styrene-butadieiie resin (ABS resin) is added 10 parts of carbon black and 5 parts of tetrakis[3',5-di-(u-methylbenzy1)-4 hydroxyben- 'zyllphosphonium chloride. The mixture is blended in a v Banbury mixer, resulti'ngina highly stable ABS'iesirij EXAMPLE 21 To 1,000 parts of 'a gasolinelcontaining 26.6 percent aromatics, 20.8 percent olefins, 52.6 percent saturates and having an API gravity of 62.1 is added '10 parts of tetrakis( 3,5 di sec dodecyl 4 hydroxybenz'yhphos- 'phonium bromide. The resulting gasoline is stable."-'

EXAMPLE 22 To 10,000 parts of gasoline containing 8.6 "percent aromatics, 7.9 percent olefins, 8315 percent saturates and having an API gravity.of 68.5 is added parts of tetrakis(3,5 dicyclohexyl 4 hydroxybenzyl)phosphonium bromide. The resulting gasoline is stable against 'oxidative degradation.

EXAMPLE 23 5 A I To 10,000 parts of a gasoline icOntiainin'giZOLO pereent aromatics, 41.2 percent olefins, 38.8 percent saturates and containing additionally 1.5 grams of manganese per galvlon as methyl cyclopentadienyl manganese tricarbonyl is added 5-0 parts of tetrakis(3,5di-tert-octyl-4 hydroxybenvzyl)phosphonium chloride. The resulting gasoline containing a manganese antiknock was resistantltooxidative degradation.

1 1 EXAMPLE 24 To 10,000 parts of a gasoline containing 20.5 percent aromatics, 32.9 percent olefins and 46.6 percent saturates and containing 2.39 grams per gallon of tetraethyllead and one theory of chlorine as ethylenedichloride and 0.5 theory of bromine as ethylenedibromide is added 500 parts of tetrakis( 3,5 di tert amyl 4 hydroxybenzyl)phosphonium chloride. The resulting gasoline containing a lead antiknock and halogen scavenger is resistant to oxidative degradation.

EXAMPLE 25 An antiknock fluid composition is prepared by mixing together 61.5 parts of tetraethyllead, 17.9 parts of ethylenedibromide, 18.8 parts of ethylenedichloride and 1.3 parts of tetrakis(3,5-di-tert-amyl-4-hydroxybenzyl)phosphonium chloride, resulting in a stable antiknock fluid composition.

EXAMPLE 26 To 1,000 parts of a commercial diesel fuel having a cetane number of 42 is added parts of amyl nitrate and 4 parts of tetrakis(3,5-diisopropyl-4-hydroxybenzyl) phosphonium iodide, resulting in a diesel fuel of high resistance to oxidative deterioration which does not form gum or sludge on storage.

EXAMPLE 27 To 1,000 parts of a solvent-refined neutral oil (95 viscosity index and 200 SUS at 100 F.) containing 6 percent of a commercial methacrylate VI Improver is added 5 percent of tetrakis(3,5-di-tert-butyl-4-hydroxybenzyl)phosphonium chloride, resulting in a stable lubricating oil.

EXAMPLE 28 To a solvent-refined crankcase lubricating oil having a viscosity index of 95 and a SAE viscosity of is added 0.1 percent of tetrakis[3,5-di-(a-methylbenzyl)-4-hydroxybenzylJphosphonium chloride. The resulting oil was stable against oxidative degradation.

EXAMPLE 29 EXAMPLE 30 To 100,000 parts of a commercially available pentaerythritol ester having a viscosity at 100 F. of 22.4 centistokes and known under the tradename of Hercofiex 600 is added 400 parts of tetrakis(3,5-di-tert-butyl-4-hydroxybenzyDphosphonium chloride. The resulting synthetic lubricating oil possesses improved resistance against oxidative deterioration.

EXAMPLE 3 1 To 100,000 parts of dioctyl sebacate having a viscosity at 210 F. of 36.7 SUS, a viscosity index of 159, and a molecular weight of 427 is added 250 parts of tetrakis (3-tert-butyl-5-benzyl 4 hydroxybenzyl)phosphonium iodide, resulting in a synthetic diester lubricating oil having improved resistance to oxidative degradation.

EXAMPLE 32 To 1,000 parts of a commercial coconut oil is added 5 parts of tetrakis(3,S-diisopropyl-4-hydroxybenzyl)phosphonium iodide, resulting in a vegetable oi with good aging characteristics.

12 EXAMPLE 33 To 100,000 parts of lard is added parts of tetrakis- (3,5 dicyclohexyl-4-hydroxybenzyl)phosphonium bromide resulting in a lard having resistance to rancidity.

The stabilizing additives of this invention are eminently useful as stabilizers in homopolymers and copolymers of ethylenically unsaturated monomers such as polyethylene, polypropylene, and the like. In this use they function as antioxidants and also as thermal stabilizers. They are extremely long lasting and highly resistant to the formation of color.

In order to demonstrate their superior stabilization eifect tests were conducted using a commercial polypropylene. These tests are known as Oven Aging Tests and are recognized in the plastic industry as an accurate guide to oxidative stability. In these tests small specimens of polypropylene are prepared containing the test stabilizer. These test specimens are placed in an air circulating oven maintained at C. Five replicates are made of each polypropylene-stabilizer composition and the test criteria is the time in hours until three of the five replicates show signs of deterioration. Deterioration is evidenced by cracking, discoloration or any visual appearance of change in the specimen.

Test specimens are prepared by mixing the test stabilizers with polypropylene powder for three minutes in a Waring Blendor. The mixture is then molded into a 6" x 6" sheet with a thickness of 0.025" (25 mils). This is accomplished in a molding press at 400 F. under 5,000 p.s.i. pressure. Each sheet is then cut into V2" X 1'' test specimens in order to obtain the five replicate samples. These samples are then subjected to the Oven Aging Tests.

The results obtained are shown in the following table.

The effectiveness of the present stabilizers can be en hanced still further by employing synergistic mixtures of the stabilizers of this invention. The preferred synergists are compounds having the formula:

F i Sill -C013 wherein R is a divalent hydrocarbon radical containing from 1 to about 6 carbon atoms and R is an alkyl radical containing from 6 to about 20 carbon atoms. Some examples of synergists are dilaurylthiodipropionate, diamylthiodiacetate, fi,fl'-thiobis(cetylbutyrate), dieicosylthiodiheptoate, dicetylthiodipropionate, dibenzylthiodibutyrate, didecylthiodipropionate, dihexylthiodiacetate, and the like. Preferred synergists are represented by Formula IX wherein R contains from 1-3 carbon atoms and R is an alkyl radical containing from 10 to about 18 carbon atoms. The most preferred synergists are dilaurylthiodipropionate and distearylthiodipropionate.

The ratio of synergist to stabilizing compound should be adjusted to give the desired protection at the least cost. Mixtures containing from 1 percent synergist and 99 percent stabilizer to those containing 99 percent synergist and 1 percent stabilizer can be employed. A more useful range is from 10-90 percent. Best results are usually obtained with stabilizing mixtures containing from 50 to 66 percent synergist and from 34 to 50 percent stabilizing compound.

The synergists can be employed to obtain increased stability using the same concentration of stabilizer or they can be employed to obtain the same stability with less of the stabilizer. Synergists are especially useful in this latter vention was synergized with-DLTDP.-The results obtaine I aryl radicals, C cycloalkyl radicals, C aralkyl radiwere as follows a Hours to failure Additive None i DLTDP. Tetrakis-(3,5-di-tert-butyl-4-hydroxy benzyDphosphonium chloride... Tetrakis-(3 di-tert-.butyl4-hydroxybenzyl)p osphonium chloride Plus DLTDP Con "'(wt. percent) The following table lists some useful synergistic combinations.

66%-dilaurylthiodipropionate 34%tetrakis(3,4-di-tert-butyl-4-hydroxybenzyl)phosphonium chloride 90%dicetylthiodipropionate %-tetrakis(3,5-di-tert-amyl-4-hydroxybenzyl)phosphonium chloride 10%diamylthiodiacetate 90%tetrakis(3,5-di-tert-octyl-4-hydroxybenzyl)phosphonium chloride 50%-dioctadecylthiodipropionate 50%tetrakis(3-tert-butyl-5-benzyl-4-hydroxybenzyl) phosphonium iodide wherein R and R are independently selected from the group consisting of hydrogen, C alkyl radicals, C aryl radicals, C cycloalkyl radicals, C aralkyl radicals, and X is a halogen having an atomic number from 17-53.

2. A compound of claim 1 having the formula:

R1 noQ-om-r-x I J R: 4

wherein R and R are independently selected from the group consisting of hydrogen, C alkyl radicals, C aryl radicals, C cycloalkyl radicals, C aralkyl radicals, and X is a halogen having an atomic number from 17-53.

3. The compound of claim 2 wherein R and R are tert-butyl radicals and X is chlorine.

4. A process for preparing a compound of claim 1, said r .14] process "com rising reacting about 4-6 mole parts of a hydroxybenzyl halide having the formula;

. 3 I wherein R and Rgare independently selected from the group consisting of hydrogen, C alkyl radicals, C 4

cals, and X is a halogen having-anatomic number from l7-53,.with one, Part of a-tris-hydroxyalkyl phosphine oxide havingthe-formula: g

" (Ka il/Tim" 3 wherein R is selected from the group consisting of hydrogen and C alkyl radicals, at a temperature of from about 0-200 C.

5. The process of claim 4 carried out in the presence of from about 2 to 4 mole equivalents of a tertiary amine per mole equivalent of said tris-hydroxyalkyl phosphine oxide.

6. The process of claim 5 wherein said hydroxybenzyl halide is 3,5-di-tert-butyl-4-hydroxybenzyl chloride and said tris-hydroxyalkyl phosphine oxide is tris(hydroxymethyDphosphine oxide.

7. A process of preparing a compound of claim 1, said process comprising reacting about 4-6 mole parts of a hydroxybenzyl halide having the formula:

wherein R is selected from the group consisting of hydrogen and C alkyl radicals, and X is a halogen having an atomic number from 17-53, at a temperature of from about 0-200 C.

8. The process of claim 7 carried out in the presence of from about 2 to 4 mole equivalents of a tertiary amine per mole equivalent of said tetrakis-hydroxyalkyl phosphonium halide.

9. The process of claim 8 wherein said hydroxybenzyl halide is 3,5-di-tert-butyl-4-hydroxybenzyl chloride and said tetrakis hydroxyalkyl phosphonium halide is tetrakishydroxymethyl phosphonium chloride.

10. A process for preparing a compound of claim 1, said process comprising reacting about 4-6 mole parts of a hydroxybenzyl halide having the formula:

R1 R: wherein R and R are independently selected from the group consisting of hydrogen, C alkyl radicals, C aryl radicals, C cycloalkyl radicals, C aralkyl radicals, and X is a halogen having an atomic number from 17-53, with one-mole part of a tris-hydroxyalkyl phosphine having the formula:

wherein R is selected from the group consisting of hydro- 15 16 gen and C alkyl radicals, at a temperature of from 3,146,212 8/1964 Wagner et al. 260-6065 X about 0-200 C. 3,213,057 10/1965 Ritt et al. 260-6065 X 11. The process of claim 10 carried out in the presence 3,221,057 11/ 1965 Gordon et al. 260-6065 of from about 2 to 4 mole equivalents of a tertiary amine 3,230,069 1/ 1966 Preston 260-6065 X per mole equivalent of said tris-hydroxyalkyl phosphine. 5 3,333,005 7/1967 Grayson et al 260-6065 12. The process of claim 11 wherein said hydroxy- 3,257,460 6/1966 Gordon et a1. 260-6065 benzyl halide is 3,5-di-tert-butyl-4-hydroxybenzyl chloride 3,248,429 4/1966 Baranauckas et a1. 260-6065 and said tris-hydroxyalkyl phosphine is tris-hydroxymethyl 3,422,149 1/ 1969 Rauhut et al. 260-6065 phosphine.

References Cited 10 TOBIAS E. LEVOW, Primary Examiner UNITED STATES PATENTS W. F. W. BELLAMY, Assistant Examiner 2,862,970 12/1958 Thielen 260-6065 2,946,824 7/1960 Chiddix et a1 260-6065 2,937,207 5/1960 Reuter et al. 260-6065 252-386, 399; 260-4585 mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5A 5Q6O Dated- December 9: 9 9

Inventoflp) Calvin J. Worrel It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, in Formula (III), that portion of the formula reading 9 should road I Q Column 6, line 65, in Formula (VIII) insert after the I bracket; line 69, "vol. 158" should read Vol. 159

Column 15 line 24 "tetrakis (3 Idi-" should read tetrakis- (5,5-di- Column 14, Claim 10, in the formula, that portion of the formula reading I should read SIGNED IN SEALED JUN 9 1970 Attest:

Edward M. Fletcher, It". E: 'SGHUYLER,

Auesting Officer mmissioner of Patents mg?" UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5 3,260 Dated December 9 9 9 Inventor) Calvin J. Worrel It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, in Formula (III), that portion of the formula reading 9 should read Q Column 6, line 63, in Formula (VIII), insert after the bracket; line 69, "vol. 158" should read Vol. 159 Column 15, line 2 "tetrakis(3, tdi" should read tetrakis (5,5-di- Column 14, Claim 10, in the formula, that portic of the formula reading should read SIGNED AND SEALED JUN 9 I970 Attest:

Edward M. Fletcher, In WILLIAM E; m- J'R.

Atlesting Officer Commissioner of Patents 

